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Improving bystander intervention, postresuscitation care, other strategies necessary to increase survival after cardiac arrest

Thursday, November 13 2008 | Comments

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What's This? By Selma Kaszczuk

Each link in the chain of events related to treating patients with cardiac arrest, from bystander intervention to postresuscitation care, plays a critical role in maximizing survival; however, there are several areas of particular importance as outlined recently by a panel of experts.

Survival following out-of-hospital cardiac arrest (with intervention by emergency medical service [EMS] personnel) varies regionally, with the variations being considerably more dramatic than those seen with stroke and myocardial infarction, according to Dr. Graham Nichol of the University of Washington in Seattle, who cited an analysis using data from the Resuscitation Outcomes Consortium.

"These variations are large and should be concerning both to us as clinicians but also to members of the public," he said, adding that some of the differences might be explained by not only clinical risk factors, such as age, sex, and traditional coronary parameters, but also by economic disadvantage, population density, differences in primary and secondary prevention, bystander recognition of cardiac arrest, and regional differences in EMS-related factors.

EMS-treated cardiac arrest ranks third as a cause of death in the United States, with neoplasm and other cardiac death being more prevalent, Dr. Nichol noted. He suggested that improving EMS care is critical to better survival rates.

"If we can achieve sustained and large improvements in EMS care, it can have a dramatic impact on health in this country," he commented.

Another important factor in the chain of events related to survival following cardiac arrest is bystander intervention.

"Bystander CPR clearly saves lives," said Dr. Robert Berg of the University of Arizona College of Medicine in Tucson, AZ.

In general, the rates of bystander CPR are 20% to 30%, and Dr. Berg offered several reasons for these relatively low rates. CPR can be perceived as a complicated task, and certain personal barriers may prevent action in an emergency situation. Fear of causing harm and certain disagreeable characteristics associated with CPR, such as the presence of vomit or dentures can also be factors.

Dr. Berg cited several studies demonstrating that hands-only CPR is as effective as traditional CPR, with the latter leading to a reduced rate of chest compressions per minute in a single-rescuer scenario because of pauses to deliver breaths to the collapsed individual. In fact, a lay rescuer can take as long as 16 seconds to provide 2 breaths and in turn decrease by >50% the ideal delivery of 100 chest compressions per minute.

Not only has hands-only continuous chest compression been shown to be as effective as bystander-administered traditional CPR in terms of long-term survival (15% and 16%, respectively, vs 6% for no CPR [P<.001] in one study), but the rate of good neurologic survival at 30 days appears to be much improved with the hands-only approach (19% vs 11% for hands-only vs traditional CPR), Dr. Berg said.

Bystander hands-only CPR provided by mostly untrained individuals is as good as standard CPR provided by mostly trained individuals and has become the standard for telephone-directed CPR. Dr. Berg said current bystander response to adults with sudden out-of-hospital cardiac arrest should be hands-only CPR if the bystander is untrained, or trained but not confident, and should be either hands-only or conventional CPR if the bystander is trained and confident.

In terms of providing defibrillation in a scenario of in-hospital cardiac arrest, Dr. Paul Chan of Saint Luke's Mid-America Heart Institute in Kansas City, MO, said that each minute of delay is progressively associated with worse outcomes, hence "time is of the essence." In addition to patient-related factors, he explained such delays are also influenced by hospital-related factors.

Dr. Chan cited a recent analysis showing that a primary factor related to receipt of delayed defibrillation (outside of the recommended 2-minute window after the event) was patient admission for a noncardiac reason.

"This suggests that a lot of the delays in defibrillation are explained at the hospital level," he said.

However, most conventional hospital-related factors do not appear to be associated with delayed defibrillation. These include academic status, region of the country, and the ratio of intensive care unit and telemetry beds to total hospital beds, although hospitals with patient populations >200 tend to have lower rates of delayed defibrillation.

"We as a resuscitation community need to establish quality metrics that are meaningful to ultimately improve and elevate the quality of in-hospital resuscitation and to improve survival outcomes for our patients," Dr. Chan emphasized.

Finally, strategies such as optimizing blood flow in conjunction with defibrillation are being investigated, as is postresuscitation management, including therapeutic hypothermia after cardiac arrest to improve neurologic outcomes.

"We go back to that early chain of survival image and are now more than ever aware that each link must be strong, and together those links can lead the victim of sudden cardiac arrest from the collapse to intact survival," panel co-moderator Mary Fran Hazinski of the Monroe Carell Jr. Children's Hospital at Vanderbilt in Nashville, TN, told VerusMed.

"The data are stronger than ever," she remarked. "This is the most exciting time to be involved in resuscitation research and care." (Plenary Session 12.)

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